Deng Fei, Fang Xiangning, Qiao Qinglong, Han Guoli, Miao Lu, Long Shuangshuang, Xu Zhaochao
Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
School of Chemistry and Chemical Engineering, Jinggangshan University 28 Xueyuan Road Ji'an Jiangxi 343009 China.
Chem Sci. 2025 Apr 30. doi: 10.1039/d5sc01150g.
Malachite Green (MG) and its fluorogen-activating protein (FAP) pair are valuable tools for live-cell and super-resolution fluorescence imaging due to their unique near-infrared absorption and signal enhancement. However, the low brightness and photostability of MG have limited its use in dynamic imaging. In this study, we introduce a novel derivative, azetidinly Malachite Green (Aze-MG), which enhances the brightness of the MG-FAP complex by 2.6-fold. This enhancement is achieved by replacing the ,-dimethylamino group in MG with an azetidine group, which suppresses the twisted intramolecular charge transfer (TICT) effect, leading to improved quantum yield and photostability. Additionally, the reduced binding affinity of Aze-MG for FAP enables a buffering strategy, allowing the reversible exchange of photobleached fluorogens with free fluorogens, thereby ensuring stable fluorescence over time. This combination of improved brightness and buffering capability makes Aze-MG an ideal probe for live-cell and dynamic SIM imaging.
孔雀石绿（MG）及其荧光激活蛋白（FAP）对是用于活细胞和超分辨率荧光成像的宝贵工具，因为它们具有独特的近红外吸收和信号增强特性。然而，MG的低亮度和光稳定性限制了其在动态成像中的应用。在本研究中，我们引入了一种新型衍生物氮杂环丁烷基孔雀石绿（Aze-MG），它将MG-FAP复合物的亮度提高了2.6倍。这种增强是通过用氮杂环丁烷基团取代MG中的N，N-二甲基氨基基团来实现的，这抑制了分子内扭曲电荷转移（TICT）效应，从而提高了量子产率和光稳定性。此外，Aze-MG对FAP的结合亲和力降低，使得可以采用一种缓冲策略，允许光漂白的荧光团与游离荧光团进行可逆交换，从而确保荧光随时间保持稳定。亮度提高和缓冲能力的这种结合使Aze-MG成为活细胞和动态结构光照明显微成像的理想探针。
